Sillimanite and Euclase Optical Properties

Sillimanite

Euclase

Add ⊕

Optical Properties

Luster

Vitreous, Subadamantine, Silky

Vitreous

Pleochroism

Colourless to pale brown to yellow

Weak: colorless-(greenish) yellow

Dispersion

0.020.02

0.005 1

👆🏻

Transparency

Transparent, Translucent

Refractive Index

1.653-1.6851.650-1.677

1 3.25

👆🏻

Optic Character

Crystal System

Orthorhombic

Monoclinic Prismatic H-M Symbol (2/m) Space Group: P 21/a

Birefringence

0.020-0.0220.019-0.025

0 0.296

👆🏻

Clarity

Transparent

TransparentUlrich Henn and Claudio C. Milisenda

Sillimanite and Euclase Optic Character

Sillimanite and Euclase optical properties play a significant role while distinguishing these gemstones from each other. These properties are influenced by the Sillimanite and Euclase Physical Properties like crystallographic symmetry, pleochroism,etc. in the crystal. Some of the optical properties are refractive index, luster, optic character, pleochroism etc. Prominent among these is Sillimanite and Euclase optic character. You might have noticed your gemologist rotating the gemstone while testing it. Rotating a gemstone along its optic axis helps in determining its optic character.

Compare Blue Gemstones

Sillimanite Vs Tortoiseshell

Sillimanite Vs Verdite

Sillimanite Vs Violane

Sillimanite and Euclase Transparency

Similar to their colors, Sillimanite and Euclase transparency can also be used as criteria for their primary identification. Although transparency cannot be the only criteria for gemstone identification, it can efficiently used in gemstone grading. Talking about their transparency, Sillimanite is Transparent and Translucent while Sillimanite is Transparent and Translucent in appearance.